• 1 tablespoon Dijon mustard
• 3 tablespoons white wine vinegar
• 1 tablespoon fresh lemon juice
• Pinch of sugar
• One-half cup extra virgin olive oil

• Three-quarters small red new potatoes
• Three-quarters small Yukon Gold or White Rose potatoes
• Three-quarters pound small Peruvian Blue potatoes
• 3 tablespoons extra virgin olive oil
• One-half teaspoon coarse salt
• Salt and freshly ground black pepper, to taste
• 2 tablespoons chopped shallots
• 2 tablespoons chopped fresh flat-leaf parsley

2. Prepare the dressing: Whisk together the mustard, vinegar, lemon juice, and sugar in a small bowl. Whisking constantly, slowly drizzle in the olive oil and continue whisking until the dressing is smooth and creamy. Set aside.

3. Prepare the potatoes: Wash all the potatoes well and pat them dry. Cut the potatoes in half and place them in two bowls: the gold and blue in one, the red in the other. Drizzle all with the olive oil and sprinkle with the coarse salt. Toss well to coat evenly. Place all of the potatoes in one layer on a baking sheet, keeping the red potatoes separate from the others. Roast in the center of the oven until tender, 30 minutes for the Yukon Gold and the Peruvian Blue potatoes, 45 minutes for the red. As they are cooked, transfer the potatoes to a large bowl.

4. Let the potatoes cool for 15 to 20 minutes. Then add the dressing and toss gently. Season with salt and pepper, and sprinkle with the shallots and parsley. Serve the salad at room temperature.